05000317/LER-1980-027-01, /01T-0:on 800520,following Routine Tube Cleaning on Saltwater Side of Svc Water Heat Exchanger 12,low Pressure Alarms Were Received on Subsys 11 & 12.Caused by Failed Tube in Exchanger 11 Instrument Compressor Cooler

/01T-0:on 800520,following Routine Tube Cleaning on Saltwater Side of Svc Water Heat Exchanger 12,low Pressure Alarms Were Received on Subsys 11 & 12.Caused by Failed Tube in Exchanger 11 Instrument Compressor Cooler

ML19323G978
Person / Time
Site:	Calvert Cliffs
Issue date:	06/03/1980
From:	Davis S BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19323G976	List: 05000317/LER-1980-027, Forwards LER 80-027/01T-0 05000317/LER-1980-027-01, /01T-0:on 800520,following Routine Tube Cleaning on Saltwater Side of Svc Water Heat Exchanger 12,low Pressure Alarms Were Received on Subsys 11 & 12.Caused by Failed Tube in Exchanger 11 Instrument Compressor Cooler
References
LER-80-027-01T, LER-80-27-1T, NUDOCS 8006090348
Download: ML19323G978 (2)

LER-1980-027, /01T-0:on 800520,following Routine Tube Cleaning on Saltwater Side of Svc Water Heat Exchanger 12,low Pressure Alarms Were Received on Subsys 11 & 12.Caused by Failed Tube in Exchanger 11 Instrument Compressor Cooler

Event date:
Report date:
3171980027R01 - NRC Website

text

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LICENSEE EVENT REPORT CONTROL BLOCK: l l

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LICENSE NUMBER 25 26 LICENSE TYPE JO 57 CAT 68 CON'T lol11

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8 60 61 OOCK ET NUMBER 68 69 EVENT OATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h A

10 21 I t 1750 after returning #12 service water (SRW) heat exchanaer to service 7_.

1

[

[_O # 31 Ifollowina routine tube cleanina on the saltwater side

E low oressure alarms I 7 [O

41 lwere received on both #11 and #12 SRW subsystems (T S 3.7.4.1).

At 1803 the I

l O I s I treactor was manually tripped due to main turbine high bearing temperatures

. An I

101s 1 linvestication revealed that #11 instrument air ennnressnr after a a I d l

10171 Itube and was causino air incress into the SRW system.

The leak was isolated and I

t 0 is 1 Inomal SRW flow was restored at 2145.

This is not a ranatitiva ncenrranca 7

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SUPPLt MANUP RER 33 39 36 3J CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 40 el 42 43 44 47 [The cause for air ingress into the SRW system was a failed tube in #11 instrum [iiOi l

, i., i j pompressor cooler.

As air became trapped in the idled heat exchanger air ingress f

i i 21 lexceeded the air removal cacability of the constRnt vont valvoc cancinn air hindinn I

t i i 3 I lof the system when the heat exchancer was returned to service. A desion chanop l ]

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ii i41 Iwill be imolemented to remove air comoressor coolino from the SRW system.

7 8 9 I

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80 lii5JLEJ@ l1l0l0l@l DISCOVERY OESCRIPTION HA l

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LOCATION OF RELEASE PERSONNEL ExPOSSES NUM8ER TYPE

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ISSUE

DESCRIPTION

80 PIOl NA 8 9 to I

illillllliIll; 68 69 NAME OF PREPARER S. M. Davis 80 3 i

psoug: (101) Mo_4749

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LER NO.

80-27/1T DOCKET NO.

50-317 EVENT DATE 05/20/80 REPORT DATE 06/03/80 ATTACHf1ENT EVENT DESCRIPTION AND PROBABLE CONSE00ENCES:

At 1735 #12 cleaning of #12 service wat2r heat exchanger tubes (saltwa is:

routine At 1750

. ~1 3si ;

the operator received low pressure alarms on,both #11 and #12 service subsystems:

.='it valve line-ups were immediately verified to be correct.water 1

was manually tripped at 1803 due to high main turbine bearing tenperatu uib i The reactor A subsequent investigation revealed that #11 and #12 service water

,g; res.

had become airbound.

(T.S. 3.7.4.1).

f-ms 1815. Further investigation showed that #11 instrument air compressor a y g-g_

j had tube degradation and.was suspected to be causing air ingress to th r cooler.

~~L water system.

flow restored to #11 service water system at 2030. Service water was e service 73$

i

1. 12 service water system at 2145 after satisfactorily venting the sNormal flo 22r i

p ys ten.

All reactor coolant pumps, #11 and #12 steam generators, #11 and #1 feed pumps, and the main condensor remained operable during the e ary [h

utilized to remove reactor decay heat.

vent and we This is not a repetitive occurrence.re 77 Ah CAUSE DESCRIPTION AND CORRECTIVE ACTIONS:

The cause of the air ingress into the service water system was due to a

b failure of a tube in #11 instrument air compressor af ter cooler complete system and apparently accumulated in #12 service w The compressed r"

had its outlet valve shut while tube cleaning was in progress on the salt J

side.

The service water system is e water to maintain the system free of air. quipped with constant vent valves designed heat exchancer's two constant vent valves. idled heat exchanger

. ;Q JE y of the bubble was released from the idled heat exchanger. operating

~ =91F

~ IIE was returned to service the air bubble was released into the system andWhen the

~

]((][

1. 11 and #12 service water subsystems are not independent in the t

, since

==

1. 11 and #12 service water pumps lost suction causing a loss of allurbine buil 7 47 J.WE water flow.

service Corrective action to prevent recurrence is as follows service water system.has been implemented which will remove all air compresso to require the service water pump s,uction valve to be shutplant operating proced

j ;

In addition g from the "SF dead water legs while performing heat exchanger maintenance and t, eliminatin 23i operators to vent the idled pump and heat exchanger

~

.sst o require to service.

.cjc ystems

- ";3) potential for causing a gaseous ingress into the service water system

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